Reduce type constraints

[gfmio]

This PR fixes the same issue that #231 was addressing. The PR didn't properly fix the issue.

The underlying problem was that TypeScript now requires an index signature for object types as currently used in the type constraint for ValidEventMaps.

The PR relaxes the type constraint to allow arbitrary object types. The event emitter will recognise all keys K of the object type T as event names.

The existing behaviour does not change: If the type T[K] is an array type, it is used as the type of the event args. If it is a function type, the parameter type of the function becomes the type of the event args.

The new behaviour is that for keys where T[K] is neither a function nor an array type, the argument type for the event K now becomes any[].

This fixes the bug and the relaxation should offer an acceptable compromise.

[gfmio]

Here's an example:

import eventemitter3 from "eventemitter3";

interface MyEventMap {
  anEvent: () => void;
  anotherEvent: (a: number, b: string) => void;
  yetAnotherEvent: [string, number, boolean];
  invalid: string;
}

const ee = new eventemitter3.EventEmitter<MyEventMap>();

ee.emit("anEvent");
ee.emit("anotherEvent", 1, "");
ee.emit("yetAnotherEvent", "", 0, true);
ee.emit("invalid"); // works, but will suggest any[] for the event args
ee.emit("string"); // throws type error

const ee2 = new eventemitter3.EventEmitter<string>();
ee2.emit("anything"); // allows any event name and set of args

const ee3 = new eventemitter3.EventEmitter<"anEvent" | "anotherEvent">();
ee3.emit("anEvent"); // allows the "anEvent" event and any[] set of args
ee3.emit("anotherEvent"); // allows the "anotherEvent" event and any[] set of args
ee3.emit("invalid"); // throws type error

[forivall]

alternatively (diff generated using patch-package):

diff --git a/node_modules/eventemitter3/index.d.ts b/node_modules/eventemitter3/index.d.ts
index 769b427..5519d4c 100644
--- a/node_modules/eventemitter3/index.d.ts
+++ b/node_modules/eventemitter3/index.d.ts
@@ -94,7 +94,7 @@ declare namespace EventEmitter {
   export type ValidEventTypes =
     | string
     | symbol
-    | { [K in string | symbol]: any[] | ((...args: any[]) => void) | undefined };
+    | object;
 
   export type EventNames<T extends ValidEventTypes> = T extends string | symbol
     ? T
@@ -113,7 +113,7 @@ declare namespace EventEmitter {
     K extends EventNames<T>
   > = T extends string | symbol
     ? (...args: any[]) => void
-    : (...args: ArgumentMap<Exclude<T, string | symbol>>[K]) => void;
+    : (...args: ArgumentMap<Exclude<T, string | symbol>>[Extract<K, keyof T>]) => void;
 
   export type EventArgs<
     T extends ValidEventTypes,

[lpinca]

I don't use TypeScript so I don't know which one is better. I'll wait until tomorrow to keep discussion going. I would like to reach consensus on a single fix.

[forivall]

Here's my cleaner version, which doesn't go through ArgumentMap to get a single event's parameters master...forivall:fix/index-type-error-again

[lpinca]

@forivall can you open a PR?

[lpinca]

Thank you.